Running TMPGEnc 2.5 Plus, and I just got a message telling me a software DVD player has to be installed before I can see an M2V file.
Thing is, I have both a soft player, and also a seciond player installed.

Trouble began when I had an issue with the Elecard player, running out of demo.
It started showing a logo, so I uninstalled it.
I then bought WinDVD 6, but still cannot seem to get M2V playback.
All that happens at an OS level is I get messages telling me that noi stream decoder can be found.
I deregistered the Elecard codec, and I think it messed up a file called Quartz.dll, part of DirectX.
Reinstalling DirectX has not helped.
Neither did reinstalling the Elecard demo.

WinDVD 6 works okay, but I cannot see what I am doing with TMPGEnc, and that is a source of worry to me.

What can I do to get things working correctly please?

This is URGENT

EDIT.

The output from TMPGEnc Plus 2.5 is black.
I cannot see a thing.
The M2V file plays perfectly, yet there is nothing but a vlack screen when playing back the M2V file._________________www.opusproductions.com
Digital Audio Specialists

I downloaded the trial of TMPGEnc Xpress, and can see Video whilst encoding.
I still have no idea why TMPGEnc Plus 2.5 shows no output.
Or why it encodes to black screen..._________________www.opusproductions.com
Digital Audio Specialists

Where would I do this?
Please remember I'm mainly a sound engineer who also does a little bit of video encoding for hybrid DVD-A.
I'm not really used to having problems with video encoders, and do not really know where to make these changes._________________www.opusproductions.com
Digital Audio Specialists

In TMPGEnc go to Option -> Environmental Setting -> VFAPI Plug-in and then change the priority of the DirectShow loader (by right-clicking on it) to be the highest (if it's not) or to be the lowest (if it's currently the highest).

The VfW, AVI2 and DirectShow loaders can all be used to load and decode overlapping file types, and TMPGEnc has some problems determining which one it should use (i.e., will always use the first on the list). With some combinations of file format and loader you just get an error or a black screen.

Part of the blame lies with Microsoft, that has multiple different APIs do to the same job. DirectShow was supposed to have replaced the other APIs, but some things never worked under DirectShow, so some applications and some codecs have kept using the other formats, and things are a bit messy.